Cuts Out/Misses

DEFINITION
Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases, not normally felt above 1500 RPM or 48 km/h (30 mph). The exhaust has a steady spitting sound at idle, low speed or on hard acceleration for fuel starvation that can cause engine to cut out.

PRELIMINARY CHECKS
^ Preform the careful visual/physical checks as described at start of Diagnosis by Symptom. Refer to Diagnosis by Symptom. Testing and Inspection

IGNITION SYSTEM
^ Check:
- Cracked Spark plug insulators
- Burned, worn, or improperly gapped electrodes
- Heavy deposits.
- Check for cylinder miss. Refer to Chart C-4M. Chart C-4M Electronic Ignition System Misfire Diagnosis

FUEL SYSTEM
^ Check fuel system for plugged fuel filter, low pressure. Refer to Chart A-7 Fuel Testing and Inspection. Related Tests, Information and Procedures

^ Check Contaminated fuel.
^ Check injector drivers. Disconnect all injector harness connectors. Connect J-34730-2 Injector Test Light or equivalent between the harness terminal of each injector connector and note light while cranking. If test light fails to blink at any one of the connectors, it is a faulty injector drive circuit harness, connector, or terminal.
^ Perform the Injector Coil/Balance Test. Refer to Chart C-2A. Chart C-2A Fuel Injector Balance Test

ENGINE MECHANICAL
^ Check compression. Perform compression check on questionable cylinder(s) found above. If compression is low, repair as necessary.
^ Check base engine, worn camshaft lobes and valve timing. Repair as necessary

ADDITIONAL CHECKS
^ Electromagnetic Interference (EMI) interference. A missing condition can be caused by EMI on the reference circuit. EMI can usually be detected by monitoring engine RPM with a Tech 1 scan tool. A sudden increase in RPM with little change in actual engine RPM change, indicates EMI is present.
^ Intake and exhaust manifold passage for casting flash.